Intrathecal/intraventricular colistin in external ventricular device-related infections by multi-drug resistant Gram negative bacteria: case reports and review

Pharmacokinetics and pharmacodynamics of peptide antibiotics

Antimicrobial resistance is a major global health challenge. As few new efficacious antibiotics will become available in the near future, peptide antibiotics continue to be major therapeutic options for treating infections caused by multidrug-resistant pathogens. Rational use of antibiotics requires optimisation of the pharmacokinetics and pharmacodynamics for the treatment of different types of infections. Toxicodynamics must also be considered to improve the safety of antibiotic use and, where appropriate, to guide therapeutic drug monitoring. This review focuses on the pharmacokinetics/pharmacodynamics/toxicodynamics of peptide antibiotics against multidrug-resistant Gram-negative and Gram-positive pathogens. Optimising antibiotic exposure at the infection site is essential for improving their efficacy and minimising emergence of resistance.

Intrathecal/Intraventricular Colistin for Antibiotic-Resistant Bacterial CNS Infections in Pediatric Population: A Systematic Review

Central nervous system (CNS) infections constitute a life-threatening condition, especially in children. Treatment limitations exist for drug-resistant CNS bacterial infections. Inadequate CNS penetration and intravenous (IV) antibiotic treatment failure represent a major clinical challenge. However, patients with antibiotic-resistant bacterial CNS infections may benefit from intrathecal (IT) or intraventricular (IVT) colistin. The authors aimed to assess the safety and effectiveness of IT/IVT colistin therapy in the pediatric population, with or without other antibiotics, for the treatment of antibiotic-resistant CNS infections. A comprehensive literature search was conducted using the electronic databases of PubMed, Ovid, and Embase for relevant articles using the following terms: “Colistin”, “CNS infection”, and “Outcome”, as well as their combinations. The retrieved articles were filtered by age (Child), language (English), route of administration (IT/IVT), and species (Humans). The present systematic review comprised 20 articles that included 31 children (19; 61.2% were boys) with multidrug-resistant CNS infection. Their ages ranged from less than one month to 18 years (median: 9 months). Acinetobacter baumannii was the main causative organism in 22 patients (70.9%), and infection occurred mainly after neurosurgical interventions (83.8%). An external ventricular drain was inserted to administer colistin into the ventricular system in 29 cases (93.5%). The median duration for colistin therapy was 18 days. Twenty-three patients (74%) recovered, while five patients (16%) had residual disability, and three patients (10%) died. The authors concluded that IT/IVT colistin therapy is safe and effective as either the primary or adjunct treatment for antibiotic-resistant cases with CNS infection.

Intrathecal Injection of Tigecycline and Polymyxin B in the Treatment of Extensively Drug-Resistant Intracranial Acinetobacter baumannii Infection: A Case Report and Review of the Literature

Purpose

Intracranial infection after neurosurgery is one of the most serious complications, especially extensively drug-resistant (XDR) Acinetobacter baumannii (A. baumannii) seriously affects the prognosis of patients. At present, there is little experience in the treatment of this infection and limited effective treatment options, like tigecycline or polymyxin B. Therefore, this report aims to describe the efficacy of tigecycline combined with polymyxin B by intrathecal (ITH) injection in the treatment of XDR intracranial infection with A. baumannii.

Methods

We report a case of intracranial infection with XDR A. baumannii after ventricular drainage, treated by daily ITH and intravenous (IV) tigecycline, combined with polymyxin B ITH route. Moreover, tigecycline and polymyxin B treatments for XDR intracranial infection with A. baumannii that were reported in the literature were also reviewed and summarized.

Results

The white blood cells (WBCs) of the patient’s cerebrospinal fluid dropped to normal, and the symptoms of intracranial infection disappeared. The patient finally obtained good clinical results and transferred to the local hospital.

Conclusion

The polymyxin B ITH route is an ideal treatment strategy for XDR A. baumannii. The IV plus ITH tigecycline may be an effective treatment option. However, more researches should be conducted to confirm our observation.

Indian Society of Pediatric Neurosurgery Consensus Guidelines on Preventing and Managing Shunt Infection: Version 2020-21

Background

Shunt infection is the most significant morbidity associated with shunt surgery. Based on the existing literature for the prevention and management of shunt infection, region and resource-specific recommendations are needed.

Methods

In February 2020, a Guidelines Development Group (GDG) was created by the Indian Society of Paediatric Neurosurgery (IndSPN) to formulate guidelines on shunt infections, which would be relevant to our country and LMIC in general. An initial email survey identified existing practices among the membership of the IndSPN, and eight broad issues pertaining to shunt infection were identified. Next, members of the GDG performed a systematic review of the literature on the prevention and management of shunt infection. Then, through a series of virtual meetings of the GDG over 1 year, evidence from the literature was presented to all the members and consensus was built on different aspects of shunt infection. Finally, the guidelines document was drafted and circulated among the GDG for final approval. Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to grade the evidence and strength of recommendation.

Results

The guidelines are divided into eight sections. Level I and Level II evidence was available for only five recommendations and led to a moderate level of recommendations. Most of the available evidence was at Level III and below, and hence the level of recommendation was low or very low. A consensus method was used to provide recommendations for several issues.

Conclusions

Although most of the recommendations for the prevention and management of shunt infections are based on a low level of evidence, we believe that this document will provide a useful reference to neurosurgeons not only in India but also in other low and middle income countries. These guidelines need to be updated as and when new evidence emerges.

Clinical Features of Post-Operative Nosocomial Meningitis in Adults and Evaluation of Efficiency of Intrathecal Treatment

Background: Post-operative nosocomial meningitis is a critical complication that develops in patients after neurosurgical interventions and operations. Patients and Methods: Data were collected for 65 patients who were diagnosed as having nosocomial meningitis after neurosurgery. The agent profile, clinical and biochemical differences in gram-negative and gram-positive meningitis, and the effectiveness of intrathecal antibiotic administration in cases with carbapenem-resistant gram-negative agents were evaluated. Results: Gram-negative bacteria were isolated in 52.3% of patients. In gram-negative cases of post-operative nosocomial meningitis, white blood cell count (p = 0.015), C-reactive protein (p = 0.001), cerebrospinal fluid leukocyte count (p = 0.0001), and protein (p = 0.0001) were higher, and glucose (p = 0.002) was lower. Concurrent bacteremia (p = 0.041), 14-day mortality (p = 0.022), and 30-day mortality (p = 0.023) were higher in gram-negative cases. Empirical treatment was appropriate in 78.5% of the patients. Seventeen patients (26.2%) received intrathecal antibiotic agents in addition to intravenous antibiotic treatment because of carbapenem-resistant gram-negative bacteria. Nine (53%) of the patients receiving intrathecal therapy had Acinetobacter baumannii as the agent, six had Klebsiella pneumoniae (35.4%), one had Pseudomonas aeruginosa (5.8%), and one had Providencia rettgeri (5.8%). The mean intravenous treatment duration was 21.4 ± 10.6 (4-60) days, and the mean intrathecal treatment duration was 17.6 ± 14.0 (1-51) days. Eleven patients received colistimethate sodium intrathecally (1 × 10 mg/d), three patients received amikacin intrathecally (1 × 10 mg/d), and three patients received gentamicin intrathecally (1 × 10 mg/d). Clinical and microbiologic treatment success was achieved in nine patients (53%). Conclusions: In cases of meningitis caused by carbapenem-resistant agents, intrathecal administration of antibiotic agents such as gentamicin, amikacin, and colistin with limited blood-brain barrier transition in intravenous administration will increase survival. Therefore, intrathecal antibiotic administration should be considered as a part of routine of nosocomial meningitis.

Intraventricular treatment of paediatric meningitis due to extensively drug-resistant Gram-negative bacteria: two case reports and review of the literature

Nosocomial meningitis caused by Gram-negative bacteria is associated with increasingly common neurosurgical procedures in children, with an increase in incidence recently reported. These infections are associated with an increased risk of mortality, prolonged hospitalisation, and increased costs. In this report, we describe two paediatric cases with central nervous system infections caused by extensively drug-resistant Gram-negative bacteria that were successfully treated with intraventricular colistin. To the best of our knowledge, this is the first comprehensive review and discussion of intraventricular antimicrobial therapy in a paediatric population. Based on our comprehensive review of the relevant literature, it appears that intraventricular administration of colistin may be a promising and effective option in the treatment of central nervous system infections in children who do not respond to other treatment options.

Pharmacokinetics of colistin in cerebrospinal fluid after intraventricular administration alone in intracranial infections

The aim of this study was to investigate the pharmacokinetics of colistin in cerebrospinal fluid (CSF) after intraventricular (IVT) administration of colistin methanesulfonate (CMS) for central nervous system (CNS) infections caused by multidrug-resistant Gram-negative bacteria. Ten patients with CNS infection were treated with CMS (active substance colistin equivalent to 100 000 units, every 24 h) by IVT administration. After 3 days of treatment, the concentration of colistin in the CSF was determined by selective ultra-performance liquid chromatography (UPLC) at 2, 4, 6, 8, 12 and 24 h after CMS administration. A pharmacokinetic analysis was performed using Phoenix WinNonlin. Following IVT administration of CMS, the estimated colistin apparent CSF half-life (t_1/2) was 10.46 ± 6.98 h, the average peak colistin concentration (C_max) was 16.95 ± 7.39 μg/mL and the average time to peak concentration (T_max) was 4.6 ± 0.97 h. The measured trough concentration (C_min; colistin concentration in CSF at 24 h after administration of CMS) was 1.12-8.33 μg/mL and the average C_min was 2.91 ± 2.11 μg/mL. CSF concentrations of colistin were above the minimum inhibitory concentration (MIC) of 0.5 μg/mL at 24 h after IVT administration in all patients. Microbiological cure was observed in all patients. In conclusion, this is the first study of colistin pharmacokinetics in CSF after IVT administration alone in patients with CNS infection. It provides essential data for designing relatively safe and effective CMS dosing regimens.

Lumbar Puncture: Indications, Challenges and Recent Advances

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International Consensus Guidelines for the Optimal Use of the Polymyxins: Endorsed by the American College of Clinical Pharmacy (ACCP), European Society of Clinical Microbiology and Infectious Diseases (ESCMID), Infectious Diseases Society of America (IDSA), International Society for Anti-infective Pharmacology (ISAP), Society of Critical Care Medicine (SCCM), and Society of Infectious Diseases Pharmacists (SIDP)

The polymyxin antibiotics colistin (polymyxin E) and polymyxin B became available in the 1950s and thus did not undergo contemporary drug development procedures. Their clinical use has recently resurged, assuming an important role as salvage therapy for otherwise untreatable gram-negative infections. Since their reintroduction into the clinic, significant confusion remains due to the existence of several different conventions used to describe doses of the polymyxins, differences in their formulations, outdated product information, and uncertainties about susceptibility testing that has led to lack of clarity on how to optimally utilize and dose colistin and polymyxin B. We report consensus therapeutic guidelines for agent selection and dosing of the polymyxin antibiotics for optimal use in adult patients, as endorsed by the American College of Clinical Pharmacy (ACCP), Infectious Diseases Society of America (IDSA), International Society of Anti-Infective Pharmacology (ISAP), Society for Critical Care Medicine (SCCM), and Society of Infectious Diseases Pharmacists (SIDP). The European Society for Clinical Microbiology and Infectious Diseases (ESCMID) endorses this document as a consensus statement. The overall conclusions in the document are endorsed by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). We established a diverse international expert panel to make therapeutic recommendations regarding the pharmacokinetic and pharmacodynamic properties of the drugs and pharmacokinetic targets, polymyxin agent selection, dosing, dosage adjustment and monitoring of colistin and polymyxin B, use of polymyxin-based combination therapy, intrathecal therapy, inhalation therapy, toxicity, and prevention of renal failure. The treatment guidelines provide the first ever consensus recommendations for colistin and polymyxin B therapy that are intended to guide optimal clinical use.

Local complications of adjunct intrathecal antibiotics for nosocomial meningitis associated with gram-negative pathogens: a meta-analysis

Direct delivery of antibiotics to the ventricular system offers an alternative for the management of nosocomial meningitis. However, the available literature frequently results in controversial findings regarding its safety. The present meta-analysis aimed at summarizing the risk of local complications after the administration of intraventricular/intrathecal (IVT/IT) antibiotics for the treatment of ventriculitis/meningitis (VM) associated with gram-negative pathogens. We systematically searched the medical literature from 1964 until July 2018, for clinical studies reporting on complications after the index treatment. The quality of the eligible studies was classified as "high," "moderated," and "low" for randomized controlled trials, observational studies, and case series, respectively. The results were summarized as pooled frequencies, estimated by the random- or fixed-effects models, according to the inter-study heterogeneity. The publication bias was visualized in trim-and-fill funnel plots. Τhe analysis included twenty-three primary studies with 229 patients. The overall complication rate was as high as 0.13 (95% CI 0.08; 0.19, I² = 9%); chemical meningitis and seizures represented the majority of the complications, with an occurrence rate of 0.11 (95% CI 0.07; 0.17, I² = 0%) and 0.07 (95% CI 0.04; 0.12; I² = 0%), respectively. The meta-analysis was based on studies of "moderate" and "low" reporting quality, while the publication bias after inspecting of the funnel plots revealed significant asymmetry. The present review denotes the absence of large, high-quality studies in the field. Nevertheless, IVT/IT was associated with moderate morbidity, mainly attributed to chemical meningitis and seizures. Further high-quality studies are still required before this therapeutic modality becomes broadly established.

Polymyxin Acute Kidney Injury: Dosing and Other Strategies to Reduce Toxicity

Polymyxins are valuable antimicrobials for the management of multidrug-resistant Gram-negative bacteria; however, nephrotoxicity associated with these drugs is a very common side effect that occurs during treatment. This article briefly reviews nephrotoxic mechanisms and risk factors for polymyxin-associated acute kidney injury (AKI) and discusses dosing strategies that may mitigate kidney damage without compromising antimicrobial activity. Polymyxins have a very narrow therapeutic window and patients requiring treatment with these drugs are frequently severely ill and have multiple comorbidities, which increases the risk of AKI. Notably, there is a significant overlap between therapeutic and toxic plasma polymyxin concentrations that substantially complicates dose selection. Recent dosing protocols for both colistin and polymyxin B have been developed and may help fine tune dose adjustment of these antibiotics. Minimizing exposure to modifiable risk factors, such as other nephrotoxic agents, is strongly recommended. The dose should be carefully selected, particularly in high-risk patients. The administration of oxidative stress-reducing drugs is a promising strategy to ameliorate polymyxin-associated AKI, but still requires support from clinical studies.

Molecular Mechanisms of Neurotoxicity Induced by Polymyxins and Chemoprevention

Neurotoxicity is one major unwanted side-effects associated with polymyxin (i.e., colistin and polymyxin B) therapy. Clinically, colistin neurotoxicity is characterized by neurological symptoms including dizziness, visual disturbances, vertigo, confusion, hallucinations, seizures, ataxia, and facial and peripheral paresthesias. Pathologically, colistin-induced neurotoxicity is characterized by cell injury and death in neuronal cell. This Review covers our current understanding of polymyxin-induced neurotoxicity, its underlying mechanisms, and the discovery of novel neuroprotective agents to limit this neurotoxicity. In recent years, an increasing body of literature supports the notion that polymyxin-induced nerve damage is largely related to oxidative stress and mitochondrial dysfunction. P53, PI3K/Akt, and MAPK pathways are also involved in colistin-induced neuronal cell death. The activation of the redox homeostasis pathways such as Nrf2/HO-1 and autophagy have also been shown to play protective roles against polymyxin-induced neurotoxicity. These pathways have been demonstrated to be upregulated by neuroprotective agents including curcumin, rapamycin and minocycline. Further research is needed toward the development of novel polymyxin formulations in combination with neuroprotective agents to ameliorate this unwanted adverse effect during polymyxins therapy in patients.

Use of Colistin in Critically Ill Patients

Due to lack of better therapeutic options, colistin use for extensively drug-resistant Gram-negative organisms was revived in the past two decades, including in patients in intensive-care units (ICU). There are multiple knowledge gaps pertaining to the clinical use and utility of colistin in critically-ill patients, but due to lack of options, it is used in these high risk patients. In this chapter, we critically review the various topics pertaining to colistin use in critically-ill patients, while highlighting the (lack of) controlled evidence supporting common current practices pertaining to colistin use by clinicians.

Colistin for Treatment of Multidrug Resistant Central Nervous System Infection: A Triple Route Therapy!

How to cite this article: Shukla RK, Kapoor I, Mahajan C, Prabhakar H. Colistin for Treatment of Multidrug Resistant Central Nervous System Infection: A Triple Route Therapy!. Indian J Crit Care Med 2019;23(6):287.

Clinical Use of Colistin in Biofilm-Associated Infections

Biofilm is an adaptive bacterial strategy whereby microorganisms become encased in a complex glycoproteic matrix. The low concentration of oxygen and nutrients in this environment leads to heterogeneous phenotypic changes in the bacteria, with antimicrobial tolerance being of paramount importance. As with other antibiotics, the activity of colistin is impaired by biofilm-embedded bacteria. Therefore, the recommendation for administering high doses in combination with a second drug, indicated for planktonic infections, remains valid in this setting. Notably, colistin has activity against metabolically inactive biofilm-embedded cells located in the inner layers of the biofilm structure. This is opposite and complementary to the activity of other antimicrobials that are able to kill metabolically active cells in the outer layers of the biofilm. Several experimental models have shown a higher activity of colistin when used in combination with other agents, and have reported that this can avoid the emergence of colistin-resistant subpopulations. Most experience of colistin in biofilm-associated infections comes from patients with cystic fibrosis, where the use of nebulized colistin allows high concentrations to reach the site of the infection. However, limited clinical experience is available in other scenarios, such as osteoarticular infections or device-related central nervous system infections caused by multi-drug resistant microorganisms. In the latter scenario, the use of intraventricular or intrathecal colistin also permits high local concentrations and good clinical results. Overall, the efficacy of intravenous colistin seems to be poor, but its association with a second antimicrobial significantly increases the response rate. Given its activity against inner bioflm-embedded cells, its possible role in combination with other antibiotics, beyond last-line therapy situations, should be further explored.

Clinical Pharmacokinetics, Pharmacodynamics and Toxicodynamics of Polymyxins: Implications for Therapeutic Use

The availability of sensitive, accurate and specific analytical methods for the measurement of polymyxins in biological fluids has enabled an understanding of the pharmacokinetics of these important antibiotics in healthy humans and patients. Colistin is administered as its inactive prodrug colistin methanesulfonate (CMS) and has especially complex pharmacokinetics. CMS undergoes conversion in vivo to the active entity colistin, but the rate of conversion varies from brand to brand and possibly from batch to batch. The extent of conversion is generally quite low and depends on the relative magnitudes of the conversion clearance and other clearance pathways for CMS of which renal excretion is a major component. Formed colistin in the systemic circulation undergoes very extensive tubular reabsorption; the same mechanism operates for polymyxin B which is administered in its active form. The extensive renal tubular reabsorption undoubtedly contributes to the propensity for the polymyxins to cause nephrotoxicity. While there are some aspects of pharmacokinetic behaviour that are similar between the two clinically used polymyxins, there are also substantial differences. In this chapter, the pharmacokinetics of colistin, administered as CMS, and polymyxin B are reviewed, and the therapeutic implications are discussed.

Efficacy of intraventricular amikacin treatment in pan-resistant Pseudomonas aeruginosa postsurgical meningitis

Background

We describe a case of pan-resistant Pseudomonas aeruginosa postsurgical meningitis associated with the presence of an external ventricular device. We changed therapy twice; finally, by using amikacin and a continuous infusion of cefepime, we obtained clinical improvement.

Case presentation

A female patient, who underwent surgery for a cavernous angioma, presented with meningitis. Cerebrospinal fluid culture revealed a multidrug-resistant Pseudomonas aeruginosa, initially sensitive only to colistin. We successfully used intrathecal amikacin and intravenous cefepime continuous infusion plus intravenous amikacin after two previous ineffective therapeutic approaches.

Conclusion

The evaluation of the antibiotic concentration and the bactericidal activity in cerebrospinal fluid may contribute to the choice of the drug in cases of multidrug-resistant meningitis.

Persistent Gram-negative Neurosurgical Meningitis in a Neonate, Successfully Treated With Intraventricular Colistin: Case Report and Review of the Literature

We present a case of Gram-negative neurosurgical meningitis in a neonate, refractory to optimal intravenous therapy and removal of ventriculoperitoneal shunt. Cerebrospinal fluid was sterilized within 24 hours using intraventricular colistin. This is the first report of intraventricular colistin use in neonatal meningitis caused by Enterobacter cloacae.

Polymyxins for CNS infections: Pharmacology and neurotoxicity

Central nervous system (CNS) infections caused by multi-drug resistant (MDR) Gram-negative bacteria present a major health and economic burden worldwide. Due to the nearly empty antibiotic discovery pipeline, polymyxins (i.e. polymyxin B and colistin) are used as the last-line therapy against Gram-negative 'superbugs' when all other treatment modalities have failed. The treatment of CNS infections due to multi-drug resistant Gram-negative bacteria is problematic and associated with high mortality rates. Colistin shows significant efficacy for the treatment of CNS infections caused by MDR Gram-negative bacteria that are resistant to all other antibiotics. In particular, MDR Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae which are resistant to expanded-spectrum and fourth-generation cephalosporins, carbapenems and aminoglycosides, represent a major therapeutic challenge, although they can be treated with colistin or polymyxin B. However, current dosing recommendations of intrathecal/intraventricular polymyxins are largely empirical, as we have little understanding of the pharmacokinetics/pharmacodynamics and, importantly, we are only starting to understand the mechanisms of potential neurotoxicity. This review covers the current knowledge-base on the mechanisms of disposition and potential neurotoxicity of polymyxins as well as the combined use of neuroprotective agents to alleviate polymyxins-related neurotoxicity. Progress in this field will provide the urgently needed pharmacological information for safer and more efficacious intrathecal/intraventricular polymyxin therapy against life-threatening CNS infections caused by Gram-negative 'superbugs'.

Evaluation of intraventricular colistin utilization: A case series

PURPOSE

Multi-drug resistant organisms (MDROs) are an increasing concern in health systems. Pathogens such as Pseudomonas aeruginosa, Acinetobacter baumanii, and carbapenamase-producing Enterobacteriaceae hold highest mortality rates especially when the central nervous system is involved. When MDROs are cultured treatment options are limited and reliance on medications such as colistin is becoming more prevalent. Penetration of these therapies into the central nervous system is concerning therefore local administration is a potential concomitant therapy.

METHODS

This study was a retrospective review from 2009 to 2015 for all patients with documented MDROs gram negative pathogens who received intraventricular colistin.

RESULTS

Seven patients met inclusion criteria. The average age of the patients was 49years old, 4 were males, and the median length of intensive care unit stay was 30days. The duration of therapy ranged from 2 to 14days and all cerebrospinal fluid cultures were sterile at 7days after administration of colistin. Six of the seven patients were discharged from the hospital and one discharged to a skilled nursing facility. The use of intraventricular colistin was not associated with any reported adverse events.

CONCLUSION

The use of intraventricular colistin was associated with positive clinical outcomes with no reported adverse effects.

Clinical characteristics, microbiology and outcomes of external ventricular drainage-associated infections: The importance of active treatment

Data concerning clinical characteristics, microbiology, treatment and outcomes of external ventricular drainage-associated infections (EVDAI) are limited. All hospitalized patients with EVDAI in a University Hospital between January 2009 and December 2015 were retrospective recorded. Only the first episode per patient was included. An antibiotic was considered "active" when its pharmacokinetic properties were appropriate for EVDAI and the implicated microorganism was in vitro susceptible. During the 7-year study period, 36 EVDAI were identified. Median patient age was 53years and 23 (63.9%) were male. Catheter types were intraventricular (70.6%) and lumbar (29.4%). Median catheterization duration before infection was 14days. Gram-negative bacteria (GNB) predominated (57.9%), followed by gram-positives (36.8%) and fungi (5.3%). Administered antibiotics were considered "active" in 69.4% of empirical and in 86.1% of definitive treatment regimens. In 10 infections, intraventricular/intrathecal (IVT) antibiotics were administered. Eleven patients died (30.6%) during hospitalization. Patients who died had higher rates of EVDAI by GNB (p=0.011) and higher rates of treatment with intravenous colistin (p=0.019 for empirical and p=0.006 for definitive colistin). Compared to EVDAI by other pathogens, patients with EVDAI by GNB had longer catheter-days before infection (p<0.001) and higher mortality (p=0.011). In our study, GNB were a frequent cause of EVDAI, and were related with high rates of inactive treatment and mortality. Intravenous colistin alone is not effective and treatment should include IVT antibiotics and intravenous antibiotics that achieve adequate CSF levels.

Frequent use of colistin-based drug treatment to eliminate extended-spectrum beta-lactamase-producing Escherichia coli in backyard chicken farms in Thai Binh Province, Vietnam

Reports of livestock infections with extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E) are increasing. Based on interviews conducted over a 6-month period, we found that veterinarians in the Vietnamese province of Thai Binh prefer to prescribe colistin-based drugs (CBD) in chicken farms. We aimed to clarify whether CBD use selects for strains of colistin-resistant ESBL-E. With the cooperation of seven local households, we detected ESBL-E in chickens' feces after treating chickens with CBD. Phylogenetic groupings and the presence of CTX-M/AmpC genes were determined, and the multi-antibiotic susceptibility of isolates was analyzed. Our results showed that ESBL-E presented in seven chickens' feces from two households. Seventy-two percent of ESBL-E isolates harbored CTX-M9 and the phylogenetic group A; the colistin minimum inhibitory concentration (MIC) of all isolated ESBL-E ranged from 0.064 to 1 μg mL^-1. Moreover, ESBL-E isolates were used to experimentally select for colistin resistance, and the effect of commercial CBD on ESBL-E was investigated. The results showed that an ESBL-E strain with a colistin MIC of 4 μg mL^-1 was able to grow in media with CBD. Although CBD treatment was effective, in vitro experiments demonstrated that ESBL-E can easily acquire colistin resistance. Therefore, restrictions on colistin use are necessary to prevent the emergence of colistin-resistant bacteria.

Colistin and tigecycline for management of external ventricular device-related ventriculitis due to multidrug-resistant Acinetobacter baumannii

Acinetobacter baumannii is an important cause of nosocomial ventriculitis associated with external ventricular device (EVD). It is frequently multidrug resistant (MDR), carries a poor outcome, and is difficult to treat. We report a case of MDR Acinetobacter ventriculitis treated with intravenous and intraventricular colistin together with intravenous tigecycline. The patient developed nephrotoxicity and poor neurological outcome despite microbiological cure. Careful implementation of bundle of measures to minimize EVD-associated ventriculitis is valuable.

Outcomes in meningitis/ventriculitis treated with intravenous or intraventricular plus intravenous colistin

BACKGROUND

The aim of this work is to evaluate the outcome of patients treated with intrathecal colistin for meningitis/ventriculitis.

METHODS

This retrospective case series study included patients presenting with nosocomial meningitis/ventriculitis following neurosurgical interventions and having intravenous (IVC group) or intravenous and intrathecal/intraventricular colistin (ITC group) treatment between 2006 and 2014.

RESULTS

Thirty-four patients presented nosocomial meningitis/ventriculitis; 11 (32.5 %) were included in the IVC group and 23 (67.6 %) in the ITC group. The most frequent isolated bacteria were Acinetobacter baumannii. The mean dose was 170,000 (±400) IU and the duration of intraventricular treatment was 16.0 (±8.3) days. The duration of intravenous treatment was 16.0 (±8.3) days in the ITC group and 15.3 ± 7.6 days in IVC group. Hospital mortality was significantly lower in the ITC group compared with the IVC group (13 vs. 72.7 %, p = 0.001).

CONCLUSIONS

The combination of intravenous plus intraventricular (IV-IVT) colistin therapy may improve outcomes in patients attending with meningitis/ventriculitis due to multi-drug resistance infections.

Intrathecal administration of colistin for meningitis due to New Delhi metallo-β-lactamase 1(NDM-1)-producing Klebsiella pneumoniae

Infection by bacteria carrying New Delhi metallo-β-lactamase 1 (NDM-1) is becoming a global health problem. We report a case of meningitis caused by NDM-1-producing Klebsiella pneumoniae, for which intrathecal administration of colistin was curative. A previously healthy 38-year-old Japanese man, who lived in Hyderabad, India, suddenly collapsed and was brought to a local hospital. He was diagnosed with subarachnoid hemorrhage and underwent emergency surgery which included partial skull removal. Approximately 1 month after surgery, he was repatriated to Japan and was admitted to our institution with information that he had been treated for multi-drug resistant Acinetobacter infection with colistin. A week after admission, he developed aspiration pneumonia due to NDM-1-producing K. pneumoniae, which was successfully treated by intravenous (IV) administration of colistin. Subsequently, he underwent a surgical procedure to repair his skull defect. He developed high-grade fever and altered mental status on postoperative day 2. NDM-1-producing K. pneumoniae was identified in the cerebrospinal fluid, establishing the diagnosis of meningitis. Although IV colistin was only partially effective, intrathecal colistin (10 mg daily by lumbar puncture for 14 days) successfully eradicated the meningitis. Because of economic globalization, NDM-1-producing bacteria may be brought to Japan by those who are repatriated after sustaining critical illnesses and being treated in foreign countries. This report may provide useful information on the treatment of central nervous system infection by NDM-1-producing bacteria.